Because neon underglow isn't on that list of regulations, it's not permitted to have a car with them. Some states have more vague instructions, such as Delaware and New Jersey.

Govee Govee Exterior Car LED Lights, RGBIC Underglow Car Lights with App and Remote Control, 16 Million Colors, Music Mode, DIY Mode, 10 Scene Modes for SUVs, Trucks. $50 at Amazon.

The Nilight Car Underglow Neon Accent Strip Lights are just $26 right now on Amazon. Shoppers say they’re “super bright,” “durable,” and make their cars glow.

The underglow rules stated in the Society of Automotive Engineers (SAE) standards say: Red, blue, purple and green underglow lights are not allowed because they are reserved for emergency vehicles ...

Because neon underglow isn't on that list of regulations, it's not permitted to have a car with them. Some states have more vague instructions, such as Delaware and New Jersey.